Queensland's QIMR Berghofer Medical Research Institute has developed a breakthrough vaccine candidate against the widespread but little-known cytomegalovirus, or CMV, which can cause severe disabilities among unborn babies.
CMV is a herpes virus which is carried by half the population, but the majority will never develop symptoms. A small proportion develop a glandular fever-like illness. However, in pregnant women, CMV is potentially dangerous for their unborn baby and may cause permanent hearing loss, cerebral palsy and even death. The virus is also dangerous for transplant patients due to their compromised immune system.
Development of a CMV vaccine has been a top priority of the US Institute of Medicine but so far, all attempts to produce a durable and effective CMV vaccine have failed.
QIMR Berghofer's breakthrough represents a new approach. Professor Rajiv Khanna, coordinator of the Institute's Centre for Immunotherapy and Vaccine Development, said previous attempts had failed because they relied on traditional technologies to develop antibodies which attach to and remove the virus.
"CMV is a very complex virus, one of the largest DNA viruses, and it can hide inside cells and escape immune control," Professor Khanna explained.
"What we have done is to deploy another arm of the immune system, what we call Killer T-Cells, to attack those cells in which the virus is hiding.
"We are combining both humoral immunity and this killer cellular immunity into a single formulation," Professor Khanna said.
Extensive preclinical testing of this bivalent vaccine has produced strong neutralising antibody and CMV-specific polyfunctional T cell responses. The QIMR Berghofer team has also successfully developed a process to produce the vaccine's polyepitope protein. Professor Khanna's work is published in PLOS Pathogens Journal.
CMV Support Group Celebrates Breakthrough
News of the breakthrough has been applauded by the national body supporting families affected by CMV. President of CMV Australia, Kate Daly is the mother of twins, one of whom was left with serious disabilities caused by CMV.
"This long-awaited breakthrough is wonderful news that will hopefully one day save families from going through the heartache that many like us have endured, learning that their baby's disability was caused by a virus."
"Despite being a very common virus, many families have never heard of CMV until they are impacted by it. While a vaccine will be a wonderful development, in the meantime, it's critical to raise awareness about CMV," Kate said.
Brisbane mother Miff Ward had also not heard of CMV until she learnt she was infected during her pregnancy. Her baby Azaria was born with permanent hearing loss.
"It was a really difficult and emotional time for us. Our first baby, going through all that excitement, and then halfway through for this to happen," Miff said.
"We were lucky that the effects of CMV were not more severe considering what can happen. It's surprising that there is so little awareness of such a common virus that can cause so much damage to an unborn baby."
"I wouldn't wish our experience on my worst enemy so I'm really excited to learn that a vaccine may be coming and other families won't have to experience this," Miff said.
CMV is most commonly spread through saliva and other bodily fluids, and pregnant women are urged to be diligent about basic hygiene to minimise the chance of contracting the virus. These include not sharing utensils with young children and generally avoiding saliva contact with children.
